VB.Net MySQL 如何向数据库中插入值 [英] VB.Net MySQL How to insert values to the database

问题描述

Pro Devs 我正在使用 VB.Net 和 MySQL 数据库，我想在我的数据库中插入值.示例:我的数据库中有值 Admin11，但是当我插入另一个值 admin11 时，我的代码出现错误.顺便说一下，这两个方法在不同的类中.

Pro Devs I'm using VB.Net with MySQL Database and I want to insert values in my DB. Example: I have values in my DB which are Admin11 but when I insert another value admin11 I get an error here's my code. by the way, these two methods are in different classes.

'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''

'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''

这是我的代码，用于检查数据库中是否存在用户名...

here's my code to check if Username exists in the database...

公共子检查用户名IfExist()

Public Sub checkUsernameIfExist()

    Dim con = New MySqlConnection
    con.ConnectionString = "server=localhost;userid=root;password=alpine;port=3305;database=pos_db;pooling=false;SslMode=none"

    con.Open()
    Dim query As String = "SELECT Username FROM pos_db.tblusers WHERE BINARY Username=@Users"
    Dim cmd As New MySqlCommand(query, con)
    cmd.Parameters.AddWithValue("@Users", frmLogin.txtUser.Text)

    Dim count As Integer = Convert.ToInt32(cmd.ExecuteScalar())

    If count <> 0 Then
        MessageBox.Show("Username is already taken. Please create a unique one!", "System", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
        Return
    Else
        insertDataToTblUser.insertToLogin()
    End If
    con.Close()
    con.Dispose()
End Sub

'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''

''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''

这是我在插入值中的代码......

Here's my code in insert values......

Dim con As MySqlConnection

Dim con As MySqlConnection

Public Sub insertToLogin()
    con = New MySqlConnection
    con.ConnectionString = "server=localhost;userid=root;password=alpine;port=3305;database=pos_db;pooling=false;SslMode=none"

    con.Open()

    Dim qry As String = "INSERT INTO tblUsers (Username,Password,Level) VALUES (@User,@Pass,@lvl)"
    Dim cmd As New MySqlCommand(qry, con)
    cmd.Parameters.AddWithValue("@User", frmLogin.txtUser.Text)
    cmd.Parameters.AddWithValue("@Pass", frmLogin.txtPass.Text)
    cmd.Parameters.AddWithValue("@lvl", frmLogin.cmbUserlevel.Text)
    cmd.ExecuteNonQuery()

    MessageBox.Show("Sign Up Successful", "System", MessageBoxButtons.OK, MessageBoxIcon.Information)

    con.Close()
    con.Dispose()
End Sub

请帮助我，非常感谢.

推荐答案

这些解决了我的问题 感谢所有帮助我的人.

These solves my problem Thanks to all who help me.

CREATE TABLE `pos_db`.`tblForLogin` (
    `Username` VARCHAR(50) CHARACTER SET utf8mb4 COLLATE utf8mb4_bin NOT NULL UNIQUE, 
    `Password` VARCHAR(50) NOT NULL,
    `Level` VARCHAR(50) NOT NULL, 
    PRIMARY KEY(Username)
);

这篇关于VB.Net MySQL 如何向数据库中插入值的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！